海南岛稻田饰纹姬蛙的食性分析

对采自海南岛稻田的414只饰纹姬蛙,采用洗胃法作食性分析,分别计算了它们的食物数量和频次百分比、多样性指数、百分率相似性指数、营养生态位宽度、营养生态位重叠值和有益系数等．分析和统计的结果显示,饰纹姬蛙共取食了6纲19目59科的物种,雌雄个体的取食食性差异不显著,不同季节的取食食性差异也不显著,总有益系数、不同性别及不同季节的有益系数分别为V总=52．8％、V♀=57．26％、V♂=51．13％、V春=39．88％、V夏=40．68％、V秋=22．76％、V冬=60．47％．     

历史文化名镇的构成要素——以山西省代县阳明堡镇为例

以山西省代县阳明堡镇为例,通过对该历史文化名镇的构成要素的分析与研究,探讨了阳明堡古镇在从一个军事镇发展到一个商业集镇的演变过程中其主要构成要素的变化,分析了其所携带的历史信息的变化,从而总结出阳明堡镇发展的历史脉络和规律,对历史文化名镇的保护具有重要意义。     

茶树油芳香水的化学成分分析

采用色谱-质谱-计算机（GC—MS—DS）联用方法分析水蒸汽蒸馏法提取茶树挥发油的茶树油芳香水中溶于（或微溶于）水的芳香化学组分,并与茶树油的化学成分进行对比。结果从茶树油芳香水中分离出40多个组分,确认了其中22种成分,占色谱总馏出峰面积的90％以上。茶树油芳香水和茶树油样品的色谱基本相同,化学成分既有共同也有不同,但主要化学成分基本一致。水蒸汽蒸馏法提取茶树挥发油的茶树油芳香水可以采用复馏工艺回收溶于水的轻组分以提高得油率,也可以开发成天然的医药保健、灭菌消毒、美容护肤、洗涤等新产品。     

Detection of 2,4-dinitrotoluene using hydrogen-bond acidic polymer coated SAW sensor

A strong hydrogen-bond acidic （HBA） polymer linear fluoroalcoholic polysiloxane （PLF）, synthesized by one-step hydrosilylation, was introduced for 2,4-dinitrotoluene （2,4-DNT） detection using surface acoustic wave （SAW） devices. FT-IR spectra and 1H NMR spectra char- acterizations confirmed its molecular structure. Then, PLF was dissolved in chloroform, and spray coated onto a 434 MHz SAW device. And subsequently, the sensitivity and selectivity of the fabricated sensor were studied based on a SAW test platform. To 2,4-DNT of 1 ppm and 100 ppb （for DNT, 1 ppm = 8.1 mg/m3; 1 ppb = 8.1 ;tg/m3）, the responses of the sensor rose 7.7 and 1.5 kHz, respectively. Furthermore, compared with some common interference vapors at 10 mg/m3, the response of the sensor to 2,4-DNT at 1 ppm was 5 times stronger. The sensitive property was attributed to the hydrogen bond interaction between the hexafluoroisopropanol （HFIP） group in PLF and the basic lone electron pairs of nitro-groups in 2,4-DNT. Comparison between the PLF sensor and hydroxyl group functionalized polymer （carbowax and MOBCD）-coated sensors was investigated, and the results showed that the PLF sensor exhibited better sensitivity. In a word, the PLF sensor exhibited fast response, negligible baseline drifts and excellent reversibility, indicating good candidates of HFIP group functionalized HBA polymers for practical nitroaromatic explosives detection.     

基于主成分分析的山东省城市竞争力评价

城市竞争力是城市综合实力的体现．本文选取山东省17个地级市的统计数据,构建拟合与表征城市竞争力的指标体系,并采用主成分分析方法,计算出17个城市的竞争力综合得分,根据聚类分析将这些城市划分为强、较强、中、较弱4类,并相应地做出综合评价．     

电子材料与元器件测试技术综合性实验的研究

本文研究了电子材料与元器件测试技术的综合性实验,论述了一般性实验和综合性实验之间的关系,制定了综合性实验的目的和要求,分析了电子04级学生的实验效果,最后指出了存在的问题和改进措施。     

家电企业竞争力测评的多元统计分析

通过主成分分析法和聚类分析法建立模型,运用SAS统计软件对国内11家家电企业的竞争力进行测评,为家电行业各企业制定合理的竞争策略提供一些依据,结果表明长虹、关的、海尔以及格力的企业竞争力比较强．     

Flow of conjunctural information and forecast of euro area economic activity

Combining forecasts, we analyse the role of information flow in computing short‐term forecasts up to one quarter ahead for the euro area GDP and its main components. A dataset of 114 monthly indicators is set up and simple bridge equations are estimated. The individual forecasts are then pooled, using different weighting schemes. To take into consideration the release calendar of each indicator, six forecasts are compiled successively during the quarter. We found that the sequencing of information determines the weight allocated to each block of indicators, especially when the first month of hard data becomes available. This conclusion extends the findings of the recent literature. Moreover, when combining forecasts, two weighting schemes are found to outperform the equal weighting scheme in almost all cases. Compared to an AR forecast, these improve by more than 40% the forecast performance for GDP in the current and next quarter. Copyright © 2010 John Wiley & Sons, Ltd.     

改性粉煤灰处理高铁高锰酸性矿井水资源化研究

治理酸性矿井水是矿山环境保护的重要内容,粉煤灰以其独有的特性对酸性矿井水有一定的处理效果.粉煤灰处理酸性高铁高锰矿井水是实现资源化利用的关键途径,同时可以达到以度治废的效果.该文利用GENESIS XM260SX-射线能谱仪(EDS)分析粉煤灰化学组分,通过NaOH、CaO、Na2CO3、NaCl、HCl、H2SO4等改性剂改性粉煤灰,以此来提高粉煤灰对酸性矿井水的处理性能,实验确定Na2CO3为最佳改性剂,出水水质达到并优于GB50335-2002《污水再生利用工程设计规范》水质指标.     

一类2个相同部件并联可修系统非零初始状态解的研究

从生产实践出发修改了系统的初始条件,推证出系统非负解的存在唯一性。